Here we go again – 2 pts each for any correct taxon name up to and including order and any supporting information you can provide. Standard ID Challenge rules apply. Hint: don’t take anything for granted – this one is going to separate the men/women from the boys/girls!

Edit 2/11/11, 8:32 a.m.: I should probably make points available for class as well (with the caveat that those with comments already in queue will get credit if due – no need to recomment unless you want to add something). Also, we’ve had enough of these by now to know that common names and “taxon by implication” generally yield fewer points than correctly presented scientific names. 🙂

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About Ted C. MacRae

Ted C. MacRae is a research entomologist by vocation and beetle taxonomist by avocation. Areas of expertise in the latter include worldwide jewel beetles (Buprestidae) and North American longhorned beetles (Cerambycidae). More recent work has focused on North American tiger beetles (Cicindelidae) and their distribution, ecology, and conservation.

Small hint – if you’re going to challenge people to identify the order of an animal in a photo, it pays not to have “beetle larvae” still visible as the mouse-over text of said photo.

Oops 😛 I guess now I have to give you the 2 pts for ‘Coleoptera’ despite that actual term not appearing anywhere in your response. You’re not the only one to think “millipede” (at least initially), but it is, in fact, a beetle larva. A lampyroid is a good guess, but the dorsal armature is rather light, the shape of the head is wrong, and my source for a 2nd opinion also agrees with my family placement.

Well, OK, here goes – let’s see how far I get before going off the rails:

Order – Coleoptera; larvae have six true legs, no sign of prolegs, and look pretty active.
Superfamily – Staphylinoidea; a number of these have armored, kind of flattened larvae, particularly the –
Family – Silphidae; which, being carrion beetles, are likely to be found in groups like that. Although, you’ve got these posed on what looks like wood that you just stripped the bark off of. Oh well, I’ve gone to far to turn back now, so forge ahead with the –
Genus – The closest thing I’ve seen locally is Necrophila (although they tend to taper to a point rather than having a blunt abdomen tip, but they do roll up, and I frequently find the local species in leaf litter and under bark rather than eating dead things, so what the heck.)

And now you’re probably going to tell us that they aren’t larvae at all, but actually adult rove beetles. Or maybe some weird kind of centipede or something. Well, I tried.

Oh, and I expect that the little gray dashes in the upper left are elongate springtails (Collembolla; Entomobryomorpha); the white skeletal-looking things in the lower center I’ll say are some kind of centipede (Myriapoda; chilopoda), and for the little shiny black dots in the upper right I’ll go for round fungus beetles (Coleoptera;Polyphaga;Staphylinoidea;Leiodidae. Although, I was tempted to call them mite eggs)

And there’s something I can’t quite make out just to the left of center (near the centipede-things) that looks like it could be a cricket nymph (Orthoptera;Gryllidae)

There! That should at least set some sort of record for most erroneous identifications in one reply, at any rate.

Yep, Coleoptera larvae, so 2 pts there, but not Silphidae, which despite their occasional occurrence under bark rather than subterranean brood chambers would not be found in such numbers actively feeding under bark. Silphid larvae also tend to be much more tapered in shape.

Good on you for noting the other organisms in the photo (which I did not realize were present at the time I was taking the photographs). The small gray dashes are, indeed Collembola (2 pts), but I put them into Podurimorpha rather than Entomobryomorpha due to their short legs and antennae. The ‘white skeletal-looking things’ are also myriapods (2 pts), but an order of millipedes rather than centipedes. The ‘shiny black dots’ are also beetles (2 pts), although I’m not sure which family they represent – Leiodidae is a good guess (although I favor ptinine anobiids). The cricket nymph is actually your entomobryomorph collembolan – sorry!

They seem to be wingless beetles (Coleoptera)… can’t quite place what kind the head and thorax remind me of. I suppose the context (under bark, among frass) should be a clue, but they don’t remind me of any wood-boring beetles I know. Looks like there are some polyxenid millipedes in there too.

I don’t know a lot about them, but they’re associated with ants, including some Lasius spp. (L. flavus & fuliginosus with P. lagurus in Europe I think), also with Temnothorax. The genus is named after a character from Greek myth, one of the first priests of Demeter and one of the first to learn the secrets of the Eleusinian Mysteries.

Yep, polyxenid millipedes (4 pts), and a bonus point for mentioning their occasional association with ants (although in the Neotropics they are better known as prey for the specialized ponerine ant Thaumatomyrmex). I don’t think it is possible to drill down to family or genus (and certainly not species) based on this photograph, so we’ll leave it at 5 pts for this.

I’ll give you 2 pts for ‘Collembola’, but my opinion is that they are something in the order Poduromorpha based on gestalt and apparent lack of long antennae. If anybody disagrees with me on this let me know. Again, impossible to drill down to family or below based on this photo, so without firmly ID’d vouchers we’ll leave it at that.

Okay, I’m going full out with this one, or at least as full out as my limited knowledge will let me.

First off, the central animals in this image are millipedes in the subclass Penicillata and its only order Polyxenida. I’m assuming from the title this picture is from your recent South American jaunt, and there are a bunch of polyxenids there, so I can’t really go any further – five individuals and what looks like a cast skin occupy the more or less centre of the picture. The penicillate ‘tails’ are the key character and the shadowy umbrellas of setae.

The peripheral elements in this picture are springtails (Collembola) with one poorly focused (shame) member of the Entomobryoidea at 7 o’clock near the polyxenids, and a diffuse array of Poduroidea on the outer left hand side (viewer’s) of the picture (taxonomy base on Penny Greenslade in CSIRO’s Insects of Australia). The entomobryoid is distinguished by its antennae, body shape, and the shiny off-purple scales. Before collembolan subfamilies got inflated to families this would have been easy, but I think it is most likely a member of the Entomobryidae – something near Sinella or Pseudosinella. The other poduroid springtails all seem to be the same and probably members of the Hypogasturidae (but since this is Brazil, could be another family). Again, body shape is distinctive.

Then there are three brown obstructions blundering through the poduroids and framing the polyxenids and entomobryid. Buggered if I know what they are, but they are not cockroaches if their antennae are any indication. That leaves beetles – strange larviform adults or armoured larvae – as one alternative, and we know that Ted loves beetles, or, since they appear to be hexapod and have similar antennae and general tagmosis, larvae of a much larger millipede (first instar millipedes being hexapod and a wonderful challenge to put on any lab practical) than the tiny polyxenids in the centre. I vote for Diplopoda, but I have no idea which one.

You should get some points solely for submitting a thesis. However, let’s go through your chapters and see where points are deserved. 🙂

Your hypothesis that the central animals are polyxenid millipedes is correct (in my opinion), and since I didn’t penalize charlie for not actually saying ‘Diplopoda’ I won’t do the same here either. 4 pts.

I also agree with our assessment of the many poduromorph and single entomobryomorph springtails, so 8 pts total for getting acceptable class- and order-level IDs for each of these. I’m going to even give you a bonus point for the thorough discussion of the characters that make them what they are.

The consensus between me and my Brazilian colleague is that the main subjects are beetle larvae (family ID revealed in followup post). I really wanted to give you the 2 pts for thinking beetle, but since your final vote was Diplopoda… It may be true that first-instar millipedes are hexapod, but at ~25mm in length the only animal large enough to have first instars this size would be an elephant (how I love hyperbole!).

I can ID those tiny milllipedes in the middle of the picture- they’re polyxenid millipedes, Class Diplopoda, order Polyxenida, but it’s pretty much impossible to ID them to family (at least for me). They’re also the prey of the specialized ponerine ant Thaumatomyrmex.

The gray flecks are springtails (Collembola).

As for those three inconspicuous black specks, they look like millipedes to me but with the first six legs greatly enlarged.

Since I didn’t penalize others for not saying ‘Diplopoda’ with the polyxenid millipedes, I’m going to give you a bonus point for including the name. You are also correct that the ones in this photo really can’t be ID’d to family and their status as prey for the specialized ponerine ant Thaumatomyrmex, which is also worth a bonus point, so 6 pts here. With 2 pts for Collembola your total is 8 pts.

As for those three inconspicuous black specks, they look like millipedes to me but with the first six legs greatly enlarged.

And, finally Part 4 – (a) the little striped beast just to bottom-left of what I think are Polyxenus, and (b) the minute shiny things dotted about here and there – at least one looks to have appendages rather than just being ‘greb’:

I’ll definitely go with Entomobryomorpha for the lone collembolan – 4 pts. I also consider the small dots to be beetles, but I can’t say for sure what family-group taxon they might be (personally, ptinine anobiids are my best guess as well), so another 2 pts. With that, your final total is 15 pts and the win!

I see a bunch of what I assume are tiny purplish springtails, class Entognatha, subclass Collembola (according to wikipedia). If they are springtails, then probably order Entomobryomorpha because they have elongated bodies.

In the lower center is a grouping of something, millipedes perhaps based on what looks like lots of legs, class Diplopoda. The white extensions they have put me in mind of order Polyxenida, though they don’t look particularly bristly here. To the left of that grouping, I see what looks like a larger springtail.

As for the three large things, I’m gonna guess they are beetles of some type, class Insecta, order Coleoptera. I’ll post another comment if I manage to narrow that down.

Tim also guessed Silphidae, but I don’t think so based on the non-tapered shape, presence of many of these larvae beneath the bark of a dead tree (suggesting xylophagy), and concurring opinion of a Brazilian colleague. You do get 2 pts for ‘Coleoptera’.

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